1. Field of the Invention
This invention relates to a cosmetic composition, and more particularly to a cosmetic composition which provides excellent moisturizing effect and excellent extendibility when applied to the skin, hair and the like, and exhibits excellent smoothness under dry and wet conditions and has excellent emulsion stability. This invention also relates to a polyol glyceryl ether which is usable as an ingredient of the above cosmetic composition.
2. Description of the Background Art
Although various moisturizers are generally incorporated in cosmetic compositions, conventional moisturizers have a problem in that they cannot provide sufficient moisturizing effects when incorporated in small amounts, and that when a large amount of moisturizer is incorporated into a cosmetic composition to sufficiently provide the moisturizing effect, the stability of the system is deteriorated.
Emulsion-type cosmetic compositions are widely used, because they can give a proper amount of oil and water to the skin and hair. Various types of emulsions which present different physical properties and give different feels to users are obtainable by changing the kind and amount of the oil.
However, since emulsions are unstable systems in terms of their thermodynamics, the stabilization of emulsions is difficult. Therefore, many studies and experiments have been carried out to solve this problem. One proposed measure is the addition of an emulsification aid having surface activity. Examples of the emulsification aid include cationic surfactants, anionic surfactants, amphoteric surfactants and nonionic surfactants, among which nonionic surfactants are the most preferred, because various oils can be used with them and they are applicable to various cosmetic compositions.
Known as a nonionic emulsification aid is a liquid-crystal-forming compound such as a higher alcohol and long chain branched alkyltriol (Japanese patent publication No. 38-5050, Japanese patent application laid-open No. 63258804); a long chain alkyl polyglyceryl ether (Japanese patent application laid-open Nos. 52-6375 and 63-23737); an ethylene oxide adduct of higher alcohol (Japanese patent application laid-open No. 62-96585); and a higher fatty acid polyol ester (Japanese patent publication No. 61-56016). These compounds, however, do not form lamellar liquid crystals when used singly, giving an oily feel to users when applied to the skin or hair. Although they form lamellar liquid crystals when combined with other ingredients, the temperature range within which lamellar liquid crystals are formed is narrow. These compounds therefore have a problem in that they cannot keep cosmetic compositions stable.
Another problem in the preparation of cosmetic compositions is explained: many active ingredients in cosmetic compositions have high melting points and they are in crystal and/or solid form at normal temperature. When they are not uniformly emulsified Or dispersed in the cosmetic composition and exist as solids and/or crystals, the effects of the ingredients such as a moisturizing effect cannot be obtained sufficiently.